CVE-2026-64034
In the Linux kernel, the following vulnerability has been resolved: net: mana: Fix TOCTOU double-fetch of hwc_msg_id from DMA buffer In mana_hwc_rx_event_handler(), resp->response.hwc_msg_id is read from DMA-coherent memory and bounds-checked, then mana_hwc_handle_resp() re-reads the same field from the same DMA buffer for test_bit() and pointer arithmetic. DMA-coherent memory is mapped uncacheable on x86 and is shared, unencrypted, in Confidential VMs (SEV-SNP/TDX), so each load goes directly to host-visible memory. A H/W can modify the value between the check and the use, bypassing the bounds validation. Fix this by reading hwc_msg_id exactly once using READ_ONCE() into a stack-local variable in mana_hwc_rx_event_handler(), and passing the validated value as a parameter to mana_hwc_handle_resp().
Affected versions
Linux kernel versions
5.13
and later are affected. Fixed in
5.15.209,
6.1.175,
6.6.142,
6.12.92,
6.18.34,
7.0.11,
7.1
and their respective stable series.
References
7 totalFrequently asked questions
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What is CVE-2026-64034?
CVE-2026-64034 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.13 onward and has been patched in 5.15.209, 6.1.175, 6.6.142 and others. CVE-2026-64034 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-64034?
Yes — CVE-2026-64034 has been patched. Fixed versions include 5.15.209, 6.1.175, 6.6.142 and others. If you are running Linux kernel 5.13 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-64034 actively exploited?
No — CVE-2026-64034 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.